Range oversampling techniques on the National Weather Radar Testbed

Faster observation of severe weather is a primary need of radar users. However, modifying scanning strategies to provide faster updates usually leads to trade-offs such as losses in data quality and/or spatial resolution. Range oversampling techniques can lead to faster updates and/or lower estimation errors without increasing the transmit bandwidth and with minimal degradation of the spatial resolution. The National Weather Radar Testbed (NWRT) is a natural platform for range oversampling research because, by default, the system oversamples in range by a factor of 4, 8, or 16. A simple pseudowhitening strategy has already been implemented and tested on the NWRT using a fixed transformation matrix. To better deal with varying conditions, an adaptive strategy is introduced that utilizes different pseudowhitening matrices based on the measured signal-to-noise ratio (SNR) and spectrum width at each range gate. Replicating the behavior of matched filtering at low SNR values is also considered. Adaptive pseudowhitening is a step towards establishing range oversampling techniques as operationally viable on weather surveillance radars.